Piezoelectric assembly, screen component, and mobile terminal

ABSTRACT

A piezoelectric assembly, a screen component, and a mobile terminal are provided. The piezoelectric assembly can include a vibrating member made of a piezoelectric material and a signal line connected to the vibrating member. The vibrating member includes two or more piezoelectric elements stacked in sequence. A size of at least one of the piezoelectric elements is smaller than a size of any remaining one of the piezoelectric elements to form a stepped structure. Each of the piezoelectric elements is provided with two or more piezoelectric layers of the same size.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority to Chinese PatentApplication Ser. No. 202010058891.1, filed on Jan. 19, 2020, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure belongs to a field of semiconductor technologies,including a piezoelectric assembly, a screen component, and a mobileterminal.

BACKGROUND

Mobile terminals, such as mobile phones or tablet computers, play anincreasingly important role in people s daily lives, and many designerspay more and more attention to user experience in the development ofmobile terminals. For example, in order to realize a high screen-to-bodyratio of mobile phones and a non-porous design for appearances of mobilephones that users pursue, screen sounding technologies are applied tothe mobile terminals to overcome a defect that holes need to be definedin middle frame assemblies of the mobile terminals to output sound fromtraditional moving coil loudspeakers. Components used to realize thescreen sounding technologies include a linear motor-type actuator, apiezoelectric-type actuator, an electromagnetic magnetic suspension-typeactuator, and the like.

In the related art, as illustrated in FIG. 1, a piezoelectric-typeactuator 100 is composed of piezoelectric ceramic elements with auniform overall thickness and the same cross-sectional area. Each of thepiezoelectric ceramic elements is composed of two or more piezoelectricceramic layers 101. All piezoelectric ceramic layers 101 have the samethickness and the same size. The deformation force output by thepiezoelectric ceramic element when energized slowly decreases in adirection from a center to a periphery, so that the piezoelectric-typeactuator 100 has a large vibration range and a broad energy distributionarea. When the piezoelectric-type actuator 100 is applied to a mobileterminal, the piezoelectric-type actuator 100 pushes a screen body tovibrate under an action of an audio signal. Consequently, a signaloutput by the piezoelectric-type actuator 100 has a large angle and poordirectivity. In addition, as an overall size of the piezoelectricceramic elements is balanced, the piezoelectric-type actuator 100occupies a large internal space of the mobile terminal, thus reducing aspace utilization rale of the mobile terminal.

SUMMARY

In this regard, the present disclosure provides a piezoelectricassembly, a screen component, and a mobile terminal.

In a first aspect of the present disclosure, a piezoelectric assembly isprovided. The piezoelectric assembly includes a vibrating member made ofa piezoelectric material and a signal line connected to the vibratingmember. The vibrating member includes two or more piezoelectric elementsstacked in sequence. A size of at least one of the piezoelectricelements is smaller than a size of any remaining one of thepiezoelectric elements to form a stepped structure. Each of thepiezoelectric elements is provided with two or more piezoelectric layersof the same size.

In a second aspect of the present disclosure, a screen component isprovided. The screen component includes a screen body and thepiezoelectric assembly as described above. A piezoelectric element ofthe largest size of the vibrating member is attached to a surface of thescreen body.

In a third aspect of the present disclosure, a mobile terminal isprovided. The mobile terminal includes a processor and a memoryconfigured to store an instruction executable by the processor Themobile terminal further includes the screen component as describedabove.

It should be understood that the above general description and thefollowing detailed description are only exemplary and explanatory, anddo not limit the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of this disclosure that are proposed asexamples will be described in detail with reference to the followingfigures, wherein like numerals reference like elements, and wherein.

FIG. 1 is a schematic view of a cross-sectional shape of piezoelectricceramic elements of a piezoelectric-type actuator having a largedeformation force distribution range and a wide signal directivity areain the related art.

FIG. 2 is a schematic view of performance indicating a concentrateddeformation force distribution range and strong signal directivity of apiezoelectric assembly according to an exemplary embodiment.

FIG. 3 is a schematic top view of a piezoelectric assembly formed bygradually reducing circular piezoelectric elements stacked at anequidistant distance according to an exemplary embodiment.

FIG. 4 is a schematic top view of a piezoelectric assembly formed bygradually reducing rectangular piezoelectric elements stacked by apreset value according to an exemplary embodiment.

FIG. 5 is a schematic top view of a piezoelectric assembly in whichrectangular piezoelectric elements do not overlap in two directionsaccording to an exemplary embodiment.

FIG. 6 is a schematic view of a piezoelectric assembly in which anoverlay element is eccentrically arranged relative to a base elementaccording to an exemplary embodiment.

FIG. 7 is a schematic view of a piezoelectric assembly in which adistance of an overlay element relative to a base element is reduced bya preset value, which illustrates a concentrated deformation forcedistribution range and tilted signal directivity.

FIG. 8 is a schematic cross-sectional view of a piezoelectric assemblyaccording to an exemplary embodiment.

FIG. 9 is a schematic view of a piezoelectric assembly applied to ascreen component according to an exemplary embodiment.

FIG. 10 is a schematic view of a screen component provided with apiezoelectric assembly applied to a mobile terminal according to anexemplary embodiment.

FIG. 11 is a schematic block diagram of a mobile terminal according toan exemplary embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings. The followingdescription refers to the accompanying drawings in winch the samenumbers in different drawings represent the same or similar elementsunless otherwise represented. The implementations set forth in thefollowing description of exemplary embodiments do not represent allimplementations consistent with the present disclosure. Instead, theyare merely examples of apparatuses and methods consistent with aspectsrelated to the present disclosure as recited in the appended claims.

Terms used in the present disclosure are for the purpose of describingspecific embodiments only, and are not intended to limit the presentdisclosure. The singular forms “a”, “said” and “the” used in the presentdisclosure and attached claims are also intended to include pluralforms, unless the context clearly indicates oilier meanings. It shouldalso be understood that terms “and/or” as used herein refer to andinclude any or all possible combinations of one or more associatedlisted items.

It should be understood that although terms such as “first”, “second”and “third” may be used to describe different information in the presentdisclosure, the information should not be limited to these terms. Theseterms are only used to distinguish the same type of information fromeach other. For example, without departing from the scope of the presentdisclosure, first information may be referred to as second information,and similarly, the second information may also be referred to as thefirst information. Depending on the context, the word “if” as usedherein may be interpreted as “when”, “while” or “in response todetermining”.

Piezoelectric ceramics and piezoelectric thin film materials arepiezoelectric materials with piezoelectric characteristics, includingpositive piezoelectricity and inverse piezoelectricity. When an externalelectric field is applied to a piezoelectric dielectric, the dielectricwill deform. For example, the piezoelectric ceramics are deformed underthe same external electric field as the spontaneous polarization, whichis equivalent to enhancing the polarization strength of thepiezoelectric ceramics. The increase in the polarization strength makesthe piezoelectric ceramics elongate in a direction of polarisation. Onthe contrary, if the piezoelectric ceramics are deformed by the externalelectric field opposite to the spontaneous polarization, thepiezoelectric ceramics are shortened along the direction ofpolarization. The phenomenon that an electrical effect of thepiezoelectric ceramics turns into a mechanical effect is an inversepiezoelectric effect. An elastic coefficient of the piezoelectricceramics is a parameter that reflects a relationship between adeformation of the ceramics and an acting force. The piezoelectricceramic materials follow Hooke's law.

As illustrated in FIGS. 2 and 3, in an embodiment, a piezoelectricassembly includes a vibrating member 200 made of a piezoelectricmaterial and a signal line 30 connected to the vibrating member 200. Thevibrating member 200 includes two or more piezoelectric elements 10stacked in sequence. A size of at least one of the piezoelectricelements 10 is smaller than a size of any remaining one of thepiezoelectric elements to form a stepped structure. Each of thepiezoelectric elements 10 is provided with two or more piezoelectriclayers of the same size. A deformation amount of the vibrating member200 matches strength of an electrical signal input from the signal line30, and a deformation force of the vibrating member 200 converges asoverlay areas of the piezoelectric elements 10 decrease. An overlay areais a projection area of a piezoelectric element 10 of a small size on apiezoelectric element 10 of a large size.

A number of stacked layers is a cumulative number of stacked layers of acurrent piezoelectric element 10 and other piezoelectric elements 10with sizes larger than the current piezoelectric element 10. Forexample, if the current piezoelectric element 10 is a thirdpiezoelectric element in a direction from a large end to a small end ofthe vibrating member 200, and each piezoelectric element has threepiezoelectric layers, an effective number of stacked layers is nine.

The vibrating member 200 is made of a piezoelectric material.Alternatively, the piezoelectric element 10 includes one of apiezoelectric thin-film material and a piezoelectric ceramic material.The signal line 30 is configured to transmit an electrical signal, sothat the vibrating member 200 is deformed when energized. Alternatively,the signal line 30 may be a flexible printed circuit (FPC) lineconnected to an electrode of each piezoelectric element 10 in thevibrating member 200.

The vibrating member 200 is formed by stacking two or more piezoelectricelements 10. For example, the vibrating member 200 is provided with two,three, four, five, six, seven, eight, nine, twelve, or any other numberof piezoelectric elements 10 stacked. A size of at least onepiezoelectric element 10 is reduced so that the vibrating member 200forms the stepped structure. Correspondingly, the vibrating member 200has an approximately conical or trapezoidal shape to reduce a spaceoccupied by the vibrating member 200. Alternatively, size ofpiezoelectric elements 10 constituting the vibrating members 200 arereduced one by one. Alternatively, the two or more piezoelectric pieces10 are of the same size partially and are stacked.

A total number of stacked layers between a small-sized piezoelectricelement 10 (abbreviated as the smallest piezoelectric element) and alarge-sized piezoelectric element 10 (abbreviated as a base element 11)is an effective number of stacked layers of the smallest piezoelectricelement. However, for an intermediate piezoelectric element between thesmallest piezoelectric element and the base element 11, the effectivenumber of stacked layers is a number of layers from the intermediatepiezoelectric element to the base element 11. Since the vibrating member200 has the stepped structure and the piezoelectric elements 10 arestacked one by one, an overlay area of each piezoelectric element 10 isa projection area of the piezoelectric element 10 on the base element11. For example, an overlay area of the smallest piezoelectric elementis a projection area of the smallest piezoelectric element on the baseelement 11. The overlay area of one intermediate piezoelectric elementis a projection area of the intermediate piezoelectric element on thebase element 11. An overlay area of the base element 11 is an area ofthe base element 11.

A calculation formula of the deformation force of the vibrating member200 is as follows:

F=(N*S)*E/D

where F represents a deformation force generated by the vibrating member200 when energized, N represents a total number of stacked layers of thepiezoelectric elements 10, S represents an overlay area of apiezoelectric element 10, D represents a thickness of each piezoelectriclayer 10, and E represents a coefficient of a piezoelectric material.

As the vibrating member 200 has the stepped structure, the overlay areadecreases as the number of piezoelectric elements 10 increases. Inaddition, the deformation force increases and concentrates as the numberof piezoelectric elements 10 increases, so as to increase aconcentration of the deformation force at a center of the vibratingmember 200. Consequently, the deformation force of the vibrating member200 decreases rapidly in a direction from a vibration center to aperiphery, thus forming the deformation force and deformation amounthaving directivity.

As illustrated in FIGS. 3, 4 and 5, in an embodiment, outer peripheraledges of two adjacent piezoelectric elements 10 do not coincide in atleast one direction. The piezoelectric elements 10 are sequentiallystacked and fired integrally to form the vibrating member 200. Apiezoelectric element 10 of a small size is slacked on a piezoelectricelement 10 of a large size. Alternatively, the outer peripheral edges oftwo adjacent piezoelectric elements 10 have no overlapping portion. Forexample, when two adjacent piezoelectric elements 10 are square, apiezoelectric element 10 of a small size is stacked on a piezoelectricelement 10 of a large size, and a center of the piezoelectric element 10of the small size and a center of the piezoelectric element 10 of thelarge size are located on the same vertical center line. The verticalcenter line is a perpendicular line perpendicular to a plane where thepiezoelectric element 10 is located and passing through a center of thepiezoelectric element 10. Alternatively, the outer peripheral edges oftwo adjacent piezoelectric elements 10 partially coincide. For example,when two adjacent piezoelectric elements 10 are square, a piezoelectricelement 10 of a small size is stacked on a piezoelectric element 10 of alarge size, and each of one or two sides of the piezoelectric element 10of the small size is aligned with a corresponding side of thepiezoelectric element 10 of the large size, and a vertical center lineof the piezoelectric element 10 of the small size and a vertical centerline of the piezoelectric element 10 of the lame size are parallel toeach other.

By adjusting a center position of overlay of the piezoelectric element10, a center direction and angle of the deformation force of thevibrating member 200 may be adjusted, so that the piezoelectric assemblyhas a controllable deformation direction and directivity, and theoperation is convenient. For example, when all the piezoelectricelements 10 are centered, a deformation center of the piezoelectricassembly is a center line of the piezoelectric assembly. When thepiezoelectric assembly is applied to an application scene of makingsound through vibration, the deformation of the piezoelectric assemblyis concentrated, and is rapidly reduced in a direction away from thecenter, which may reduce the occurrence of sound leakage and improve theprivacy of calls.

In an alternative embodiment, each of the piezoelectric elements 10includes a base element 11 having a large size and at least one overlayelement 12 stacked on the base element 11. Sizes of the overlay elements12 decrease one by one, and vertical center lines of the overlayelements 12 coincide with each other. The vertical center line is aperpendicular line perpendicular to a plane where the piezoelectricelement 10 is located and passing through a center of the piezoelectricelement 10.

The base element 11 of the largest size corresponds to the largest area.At least one overlay element 12 is stacked on the base element 11, andthe number of the overlay elements 12 may be adjusted based on designrequirements. For example, the number of the overlay elements 12 is setto one, two, three, five, eight or any other number. Sizes of theoverlay elements 12 are reduced one by one, so that the size of thepiezoelectric assembly is gradually reduced like a conical structure toreduce the space occupied by the vibrating member 200.

The vertical center lines of the overlay elements 12 coincide so thatthe deformation force output by the overlay element 12 is perpendicularto the overlay element 12, and the deformation force rapidly decreasesin a direction from a vibration center to a periphery. In addition, oneor more overlay elements 12 are stacked and form a concentrated part ofthe vibrating member 200, which facilitates the adjustment of a centralpart of the deformation force of the vibrating member 200 and improvesthe use flexibility of the piezoelectric assembly.

As illustrated in FIG. 2, in an alternative embodiment, the verticalcenter line of the at least one overlay element 12 coincides with thevertical center line of the base element 11. The vertical center line ofthe overlay element 12 is located at the vertical center line of thebase element 11, so that the deformation force of the vibrating member200 is symmetrically distributed with respect to the center, whichfacilitates the adjustment of a vibration center of a scene to which thepiezoelectric assembly is applied.

As illustrated in FIG. 6, in another alternative embodiment, thevertical center line of the at least one overlay element 12 is parallelto and does not coincide with the vertical center line of the baseelement 11. The center line of the deformation force of the vibratingmember 200 is parallel to the vertical center line of the overlayelement 12. The center line of the deformation force of the vibratingmember 200 and the vertical center line of the overlay element 12coincide with each other or slightly shift from each other to make thepiezoelectric assembly in an eccentric vibration state. Since the baseelement 11 has a large coating area, the piezoelectric assembly has goodinstallation stability. The center position of the overlay element 12 iseccentric with respect to the base element 11, which facilitates theadjustment of the direction of a vibration center of the piezoelectricassembly and improves an installation accuracy of application scenes ofthe piezoelectric assembly. For example, the piezoelectric assembly isapplied to usage scenes such as screen sounding technologies byvibration.

Sizes of the overlay elements 12 are reduced one by one to form thestepped structure. Alternatively, an outer contour shape of the baseelement 11 is the same as the shape of the overlay element 12.Alternatively, the outer contour shape of the base element 11 isdifferent from the shape of the overlay element 12. Sizes of the overlayelement 12 and the base element 11 may be adjusted based onpredetermined requirements. In an embodiment, the outer contour shape ofthe piezoelectric element 10 includes one or more of a circle, apolygon, a closed figure formed by sequentially connecting a straightline and a curve, or a closed figure formed by sequentially connectingcurves. For example, the outer contour shape of the piezoelectricelement 10 is set to a rectangle, a pentagon, a hexagon, a circle, or anellipse. For example, the overlay element 12 has an elongated shape,thus forming an elongated distribution range of the deformation force.As illustrated in FIG. 3, in an embodiment, when two or morepiezoelectric elements 10 are provided, sizes of two adjacentpiezoelectric elements 10 are equidistantly reduced. A distance betweenevery two adjacent piezoelectric elements 10 is equidistantly reduced, areduced area of an individual piezoelectric element 10 is controllable,and the controllability of the deformation force is good. Furthermore, acontrol accuracy of an attachment position between two adjacentpiezoelectric elements 10 is high, and the molding effect is good. Forexample, if the piezoelectric element 10 is configured with arectangular shape and has two overlay elements, a first overlay element12 is attached to a base element 11, and a second overlay element 12 isattached to the first overlay element 12. A distance from each edge ofthe second overlay element 12 to a corresponding edge of the firstoverlay element 12 is 2 mm.

As illustrated in FIG. 5, in another embodiment, when two or morepiezoelectric elements 10 arc provided, sizes of two adjacentpiezoelectric elements 10 are proportionally reduced. A distance betweenevery two adjacent piezoelectric elements 10 is proportionally reduced,a reduced area of an individual piezoelectric element 10 iscontrollable, and the controllability of the deformation force is good.A reduction ratio of an individual piezoelectric element 10 and theoverlay area are controllable. For example, if three overlay elements 12with a rectangular shape are provided, a first overlay element 12 isattached to a base element 11, a second overlay element 12 is attachedto the first overlay element 12, and a third overlay element 12 isattached to the second overlay element 12. The area of the secondoverlay element 12 is nine tenths of the area of the first overlayelement 12, and the area of the third overlay element 12 is nine tenthsof the area of the second overlay element 12.

As illustrated in FIG. 7, in another embodiment, when two or morepiezoelectric elements 10 are provided, a distance between edges of twoadjacent piezoelectric elements 10 is reduced by a preset value. Thedistance between edges of two adjacent piezoelectric elements 10 may beadaptively adjusted to form a deformation force that is relativelyinclined in a pointing direction.

In the embodiment, the vertical center line of each piezoelectricelement 10 is parallel to and docs not coincide with vertical centerlines of other piezoelectric elements 10, and all the piezoelectricelements 10 in the vibrating member 200 are biased in one direction,thereby forming a directional inclination angle inclined in onedirection. For example, if two overlay elements 12 with a rectangularshape are provided, and each overlay element 12 has five piezoelectriclayers, the size of the base element 11 is greater than the size of theoverlay element 12. A first overlay element 12 is attached to the baseelement 11, and a second overlay element 12 is attached to the firstoverlay element 12. Distances from edges of the second overlay element12 to edges of the first overlay element 12 are not equidistantlydistributed, so that the center of the deformation force is obliquelydistributed. A distance between one edge of the second overlay element12 and one edge of the first overlay element 12 is 2 mm, and a distancebetween an opposite edge of the second overlay element 12 and anopposite edge or the first overlay element 12 is 3 mm. A distancebetween one edge of the first overlay element 12 and one edge of thebase element 11 is 5 mm, and a distance between an opposite edge of thefirst overlay element 12 and an opposite edge of the base element 11 is10 mm.

In the middle of the screen, due to space constraints, the mounting isinconvenient. In order to increase an attachment area of thepiezoelectric assembly with the screen and to adjust the directivity ofscreen sounding through vibration, the overlay element 12 iseccentrically provided relative to the base element 11 to allow thesound to be output to a specified direction, thereby improving thedirectivity of sound wave transmission and improving the userexperience.

The deformation force is inversely proportional to the thickness of thepiezoelectric clement 10. Alternatively, thicknesses of thepiezoelectric elements 10 are the same to form a uniformly distributedstacked structure. Alternatively, the thickness of at least onepiezoelectric element 10 is different from thicknesses of otherpiezoelectric elements 10. The thickness of each piezoelectric element10 may be adjusted accordingly based on design requirements, formingrequirements for different deformation forces at the same thickness andadjusting overall thickness requirements for the piezoelectric assembly.For example, three piezoelectric elements 10 are provided, which are abase element 11, a first overlay element 12, and a second overlayelement 12. The thicknesses of the first overlay element 12 and thesecond overlay element 12 are equal. The thickness of the first overlayelement 12 is smaller than the thickness of the base element 11.

In an embodiment, a fabrication method of the piezoelectric assembly isdisclosed. The method can include the following steps.

In step 101, a surface of each piezoelectric clement 10 to be bonded iscoated with an adhesive. Two or more piezoelectric elements 10 areprovided. A size of at least one piezoelectric element 10 is smallerthan a size of any remaining one of the piezoelectric elements 10.

In step 102, the two or more piezoelectric elements 10 are stacked in aone-by-one manner by size, from large to small, to form a step-shapedpreform.

In step 103, the step-shaped preform is sintered to produce a vibratingmember 200.

In step 104, a signal line 30 is connected to the vibrating member 200to form the piezoelectric assembly. The deformation amount of thevibrating member 200 matches strength of an electrical signal input fromthe signal line 30, and the deformation force of the vibrating member200 converges as overlay areas of the piezoelectric elements 10decrease. The overlay area is a projection area of a piezoelectricelement 10 of a small size on a piezoelectric element 10 of a largesize. The signal line 30 is configured to transmit an electrical signal,so that the vibrating member 200 is deformed when energized.Alternatively, the signal line 30 may be an FPC line connected to airelectrode of the vibrating member 200.

As illustrated in FIG. 8, in the fabrication process of thepiezoelectric element 10, two or more piezoelectric layers are stackedlayer by layer to form a preform. The preform can include the followingprocessing steps.

In step 201, a first piezoelectric material layer 13 is attached to afirst electrode paste layer.

In step 202, a second electrode paste layer is coated on a surface ofthe first piezoelectric material layer 13.

In step 203, steps 201 and 202 are repeated in sequence until a numberof the piezoelectric material layers 13 meets requirements of thepreform.

The piezoelectric material layer 13 may be configured as a piezoelectricceramic layer or a piezoelectric thin-film layer. The piezoelectricmaterial layer 13 may be processed into a configured size throughcutting, molding and other processes to form a corresponding shape.Thicknesses of piezoelectric material layers 13 may be identical ordifferent.

An electrode paste layer (a1) is coated on a substrate, and apiezoelectric material layer (b1) having a stable shape is placed on theelectrode paste layer (a1). An electrode paste layer (a2) is coated on asurface of a predetermined region of the piezoelectric material layer(b1). The electrode paste layer (a2) completely covers an upper surfaceof the piezoelectric material layer (b1). A piezoelectric material layer(b2) is placed on the electrode paste layer (a2), and an electrode pastelayer (a3) is coated on a surface of the piezoelectric material layer(b2). The electrode paste layer (a3) completely covers an upper surfaceof the piezoelectric material layer (b2). Steps in this paragraph arerepeated until a number of layers of the preform meets requirements.

After the preform is sintered, the electrode paste layer forms anelectrode layer 14. The signal line 30 is conductively connected to theelectrode layer 14. The electrode layers 14 are alternately distributedto form a positive electrode and a negative electrode.

In another embodiment of the fabrication process of the piezoelectricelement 10, the piezoelectric element 10 includes a piezoelectricmaterial layer 13 and an electrode layer 14 attached to thepiezoelectric material layer 13. Stacking the two or more piezoelectricelements 10 layer by layer includes the following steps.

A surface of an electrode layer 14 of the piezoelectric layer 10 iscoated with an adhesive. A piezoelectric material layer 13 of anotherpiezoelectric layer 10 is connected to the piezoelectric element 10through the adhesive. The piezoelectric material layer 13 and theelectrode layer 14 are cut after molding, so that piezoelectric elements10 may be stacked one by one and bonded by the adhesive to form acomplete preform, which is easy to process. Interference factors such asair bubbles need to be eliminated between two adjacent piezoelectricelements 10. After the preform is sintered, the electrode layer 14serves as internal electrodes and is connected to external electrodesconnected to the signal line 30.

The vibrating member 200 is made of a piezoelectric material, and isintegrally fired after the piezoelectric elements 10 are stacked. Anelectrode layer 14 of a current piezoelectric element 10 is stacked witha piezoelectric material layers 13 of another piezoelectric element 10adjacent to the current piezoelectric element 10, and the signal line 30is conductively connected to the electrode layer 14. The electrode layer14 and the piezoelectric material layer 13 are combined with each otherto form the piezoelectric element 10. An electrode layer 14 is attachedto a surface of a base element 11, and an overlay element 12 is stackedon the electrode layer 14. Correspondingly, remaining overlay elements12 are stacked in sequence and electrically connected to the signal line30, which facilitates signal transmission and realizes high connectionefficiency. It should be noted that electrode layers 14 on both surfacesof each piezoelectric material layer 13 are a positive electrode layerand a negative electrode layer, respectively. All positive electrodelayers are connected to the same positive signal line 30 of the signalline 30, and all negative electrode layers are connected to the samenegative signal line 30 of the signal line 30.

As illustrated in FIGS. 9 and 10, the piezoelectric assembly disclosedin the above embodiments is applied to a screen component to realize ascreen sounding function. The screen component may be applied to anelectronic device such as a mobile phone, a smart bracelet, a smartwatch, a tablet computer and other types of electronic devices. Thesignal line 30 of the piezoelectric assembly is electrically connectedto an audio circuit module of the electronic device, such that changesof current parameters of the signal line 30 conform to frequencies ofaudio changes. The vibrating member 200 forms changes corresponding tothe audio changes during changes of the deformation amount and thedeformation force acting on the screen.

In an embodiment, the screen component includes a screen body 300 andthe piezoelectric assembly as disclosed in the above embodiments. Thepiezoelectric element 10 of the largest size in the vibrating member 200is attached to a surface of the screen body 300, so the screen body 300vibrates and sounds under the action of the deformation force of thevibrating member 200.

The piezoelectric element 10 of the largest size in the vibrating member200 is attached to the screen body 300, so that an attachment area ofthe piezoelectric element 10 of the largest size in the vibrating member200 and the screen body 300 is large, and thus the vibrating member 200is tightly attached to the screen body 300 The piezoelectric element 10of the largest size is one end of the vibrating member 200. Thevibrating member 200 outputs a corresponding deformation force and adeformation amount based on an electric signal transmitted by the signalline 30, and drives the screen body 300 to vibrate and sound. Since anamount of vibration output by the vibrating member 200 is concentratedand the directivity is high, the directivity of a sound wave output bythe screen body 300 through vibration and sounding is strong, whichreduces a risk of signal leakage and enhances the privacy of calls ofusers.

Alternatively, the base element 11 is attached to the screen body 300,and at least one overlay element 12 is slacked on the base element 11and may adjust lire position of a vibration center relative to thescreen body 300, thereby improving tire flexibility of adjusting andproviding a sounding region of the screen component.

In an embodiment, the vibrating member 200 is provided with an escapeportion 15 adapted to the screen body 300. The escape portion 15 isconfigured into a hole-shaped space or a notch-shaped space. The escapeportion 15 is configured to adapt to installation requirements of thescreen body 300 or internal components in the electronic device, so thatthe vibrating member 200 may avoid interference with the screen body 300or internal components in the electronic device. For example, thevibrating member 200 is configured as a circular ring structure, astructure with a blind hole, a structure with a concave notch, or thelike. The escape portion 15 may penetrate the vibrating member 200, orthe escape portion 15 is provided on the overlay element 12, so as tofacilitate the installation of the piezoelectric assembly and improvethe utilization of an internal space of the electronic device.

The vibrating member 200 is fixedly connected to the screen body 300 totransmit the deformation force of the vibrating member 200 whenenergized to the screen body 300. Alternatively, the vibrating member200 and the screen body 300 are bonded by an adhesive, such that thevibrating member 200 and the screen body 300 are tightly attached, andtransmission stability of the deformation force of the vibrating member200 is high. Alternatively, the vibrating member 200 and the screen body300 are bonded by an optical adhesive. The vibrating member 200 directlyacts on the screen body 300 and changes synchronously with a currentsignal output by the audio circuit module, and thus the quality of soundoutput by the screen component is low in distortion, and high infrequency response, and the user experience is good. In addition, thevibrating member 200 is directly attached to the screen body 300, whichrequires low for assembly and fit tolerance, reduces a product defectrate, and lowers production costs.

As illustrated in FIGS. 9 and 10. the screen component disclosed in theabove embodiments is applied to a mobile terminal, so that the mobileterminal may directionally emit sound through a screen, improvingoverall aesthetics of the mobile terminal and the privacy of calls. Inan embodiment, the mobile terminal includes a processor, and a memoryconfigured to store an instruction executable by the processor. Themobile terminal further includes the screen component as disclosed inthe above embodiments, and the signal line 30 is communicativelyconnected to the processor.

The signal line 30 is connected to the processor to transmitcorresponding audio signals. The piezoelectric assembly may control avibration frequency and amplitude of the screen body 300 based onchanges of the corresponding audio signals, and may convert the highlyconcentrated deformation force into a driving force pushing the screenbody 300 to sound. Consequently, the energy conversion efficiency ishigh, and the quality of low-band sound is high.

In an embodiment, the mobile terminal further includes a middle frameassembly 400 and a functional component 500 mounted in the middle frameassembly 400. The screen component is detachably connected to the middleframe assembly 400, and at least part of the functional component 500 islocated at a space corresponding to the stepped structure of thevibrating member 200.

The screen component is mounted in the middle frame assembly 400 andcloses an opening of the middle frame assembly 400 so that the screenbody 300 may output corresponding display information. The functionalcomponent is mounted in the middle frame assembly 400 to enable themobile terminal to perform different functions. The functional component500 includes a circuit board, components provided on the circuit board,a battery, and other components. The vibrating member 200 is formed intothe stepped structure, and an escape space is formed in an upper spacecorresponding to the piezoelectric elements 10 forming the steppedstructure. The functional component 500 may be extended into the escapespace to improve a utilization rate of on internal space of the mobileterminal. It should be noted that the piezoelectric elements 10 havedifferent thicknesses, which may be adapted to different requirements ofan installation height of the functional component 500, and improve theflexibility of the installation of the functional component 500.

As illustrated in FIG. 11, the mobile terminal may be provided asdifferent electronic devices. For example, the mobile terminal 20 may bea mobile phone, a computer, a digital broadcasting terminal, a messagingdevice, a game console, a tablet device, a medical device, a fitnessdevice, a personal digital assistant, a translating machine, and so on.

The mobile terminal 20 may include one or more of the followingcomponents: a processing component 21, a memory 22, a power component23, a multimedia component 24, an audio component 25, an input/output(I/O) interface 26, a sensor component 27, and a communication component28.

The processing component 21 normally controls the overall operation(such as operations associated with displaying, telephone calls, datacommunications, camera operations and recording operations) of themobile terminal 20. The processing component 21 may include one or moreprocessors 29 to execute instructions so as to implement all or some ofthe steps of the above method. In addition, the processing component 21may include one or more modules to facilitate interactions between theprocessing component 21 and other components. For example, theprocessing component 21 may include a multimedia module to facilitateinteractions between the multimedia component 24 and the processingcomponent 21.

The memory 22 is configured to store various types of data to supportoperations at the mobile terminal 20. Examples of such data includeinstructions for any application or method operated on the mobileterminal 20, contact data, phone book data, messages, images, videos andthe like The memory 22 may be realized by any type of volatile ornon-volatile storage devices, or a combination thereof, such as a staticrandom access memory (SRAM), an electrically erasable programmable readonly memory (EEPROM), an erasable programmable read only memory (EPROM),a programmable read only memory (PROM), a read only memory (ROM), amagnetic memory, a flash memory, a disk or an optical disk.

The power component 23 provides power to various components of themobile terminal 20. The power component 23 may include a powermanagement system, one or more power sources and other componentsassociated with power generation, management, and distribution of themobile terminal 20.

The multimedia component 24 includes a screen that provides an outputinterface between the mobile terminal 20 and a user. In someembodiments, the screen may include a liquid crystal display (LCD) and atouch panel (TP). If the screen includes a touch panel, the screen maybe implemented as a touch screen to receive input signals from the user.The touch panel includes one or more touch sensors to sense touches,slides, and gestures on the touch panel The touch sensor may sense notonly the boundary of the touches or sliding actions, but also theduration and pressure related to the touches or sliding operations. Insome embodiments, the multimedia component 24 includes a front cameraand/or a rear camera. When the mobile terminal 20 is in an operationmode such as a shooting mode or a video mode, the front camera and orthe rear camera may receive external multimedia data. Each front cameraand rear camera may be a fixed optical lens system or have a focallength and an optical zoom capability.

The audio component 25 is configured to output and/or input an audiosignal. For example, the audio component 25 includes a microphone (MIC)that is configured to receive an external audio signal when the mobileterminal 20 is in an operation mode such as a call mode, a recordingmode, and a voice recognition mode. The received audio signal may befurther stored in the memory 22 or transmitted via the communicationcomponent 28. In some embodiments, the audio component 25 is connectedto the signal line 50 so that the piezoelectric assembly vibrates thescreen to output audio signals.

The I/O interface 20 provides an interface between the processingcomponent 21 and a peripheral interface module. The peripheral interfacemodule may be a keyboard, a click wheel, buttons and so on. Thesebuttons may include, but are not limited to, a home button, a volumebutton, a start button, and a locking button.

The sensor component 27 includes one or more sensors for providing themobile terminal 20 with various aspects of status assessments. Forexample, the sensor component 27 may detect an ON/OFF slate of themobile terminal 20 and a relative positioning of the components. Forexample, the components may be a display and a keypad of the mobileterminal 20. The sensor component 27 may also detect a change inposition of the mobile technical 20 or a component of the mobileterminal 20, the presence or absence of contact of the user with themobile terminal 20, the orientation or acceleration/deceleration of themobile terminal 20 and a temperature change of the mobile terminal 20.The sensor component 27 may include a proximity sensor configured todetect the presence of nearby objects without any physical contact. Thesensor component 27 may also include a light sensor (such as a CMOS orCCD image sensor) for use in imaging applications. In some embodiments,the sensor component 27 may further include an acceleration sensor, agyro sensor, a magnetic sensor, a pressure sensor, or a temperaturesensor.

The communication component 28 is configured to facilitate wired orwireless communication between the mobile terminal 20 and other devices.The mobile terminal 20 may access a wireless network based on anycommunication standard, such as Wi-Fi, 2G, 4G, 5G, or a combinationthereof. In an exemplary embodiment, the communication component 28receives broadcast signals or broadcast-associated information from anexternal broadcast management system via a broadcast channel. In anexemplary embodiment, the communication component 28 further includes anear field communication (NFC) module to facilitate short rangecommunication. For example, in the NFC module, short range communicationmay be implemented based on radio frequency identification (RFID)technology, infrared data association (IrDA) technology, ultra-wideband(UWB) technology, Bluetooth (BT) technology, and other technologies.

In an exemplary embodiment, the mobile terminal 20 may be implemented byone or more of application specific integrated circuits (ASICs), digitalsignal processors (DSPs), digital signal processing devices (DSPDs),programmable logic devices (PLDs), field programmable gate arrays(FPGA), controllers, microcontrollers, microprocessors, or otherelectronic components to perform the above method.

The above are only preferred embodiments of the present disclosure andare not intended to limit the present disclosure. Any modification,equivalent replacement, improvement and the like made within the spiritand principles of the present disclosure shall be included in theprotection scope of the present disclosure.

What is claimed is:
 1. A piezoelectric assembly, comprising: a vibratingmember made of a piezoelectric material, the vibrating member includingtwo or more piezoelectric elements stacked in sequence, where a size ofat least one of the piezoelectric elements is smaller in size than anyremaining one of the piezoelectric elements to form a stepped structure,and each of the piezoelectric elements is provided with two or morepiezoelectric layers of a same size, and a signal line connected to thevibrating member.
 2. The piezoelectric assembly of claim 1, whereinouter peripheral edges of two adjacent Piezoelectric elements do notcoincide in at least one direction.
 3. The piezoelectric assembly ofclaim 2, wherein each of the piezoelectric elements further comprises: abase element having a large size; and at least one overlay elementslacked on the base element, wherein sizes of the overlay elementsdecrease one by one, and vertical center lines of the overlay elementscoincide with each other, where the vertical center line is aperpendicular line that is perpendicular to a plane where thepiezoelectric element is located'and that passes through a center of thepiezoelectric element.
 4. The piezoelectric assembly of claim 3, whereinthe vertical center line of the at least one overlay element coincideswith a vertical center line of the base element, or the vertical centerline of the at least one overlay element is parallel to and does notcoincide with the vertical center line of the base element.
 5. Thepiezoeletric assembly of claim 2, wherein: sizes of two adjacentpiezoelectric elements are equidistantly reduced, sizes of two adjacentpiezoelectric elements are proportionally reduced, or a distance betweenedges of two adjacent piezoelectric elements is reduced by a presetvalue,
 6. The piezoelectric assembly of claim 1, wherein all thepiezoelectric elements have the same thickness, or at least one of thepiezoelectric elements has a thickness different from that of anyremaining one of the piezoelectric elements.
 7. The piezoelectricassembly of claim 1, wherein an outer contour shape of the piezoelectricelement incudes one or more of a circle, a polygon, a closed figureformed by sequentially connecting a straight, line and a curve, or aclosed figure formed by sequentially connecting curves.
 8. Thepiezoelectric assembly of claim 1, wherein each of the piezoelectriclayers further comprises: a piezoelectric material layer; and anelectrode layer attached to the piezoelectric material layer, wherein anelectrode layer of a current piezoelectric layer is stacked with apiezoelectric material layer of another piezoelectric layer adjacent tothe current piezoelectric layer, and the signal line is conductivelyconnected to the electrode layer.
 9. The piezoelectric assembly of claim1, wherein the piezoelectric element further comprises one of apiezoelectric thin-film material and a piezoelectric ceramic material.10. A screen component, comprising: a screen body; and a piezoelectricassembly that includes a vibrating member made of a piezoelectricmaterial and a signal line connected to the vibrating member, thevibrating member includes two or more piezoelectric elements stacked insequence, wherein a size of at least one of the piezoelectric elementsis smaller in size than any remaining one of the piezoelectric elementsto form a stepped structure, each of the piezoelectric elements isprovided with two or more piezoelectric layers of the same size, and apiezoelectric element having a largest size of the vibrating member isattached to a surface of the screen body.
 11. The screen component ofclaim 10, wherein the vibrating member is provided with an escapeportion adapted to the screen body, the escape portion being configuredinto a hole-shaped space or a notch-shaped space.
 12. The screencomponent of claim 10, wherein outer peripheral edges of two adjacentpiezoelectric elements do not coincide in at least one direction. 13.The screen component of claim 12, wherein each of the piezoelectricelements further comprises: a base element having a large size; and atleast one overlay element stacked, on the base element, wherein sizes ofthe overlay elements decrease one by one, and vertical center lines ofthe overlay elements coincide with each other, where the vertical centerline is a perpendicular line that is perpendicular to a plane where thepiezoelectric clement is located and that passes through a center of thepiezoelectric element.
 14. The screen component of claim 13, wherein thevertical center line of the at least one overlay element coincides witha vertical center line of the base element, or the vertical center lineof the at least one overlay element is parallel to and does not coincidewith the vertical center line of the base element.
 15. The screencomponent of claim 12, wherein: sizes of two adjacent piezoelectricelements are equidistantly reduced, sizes of two adjacent piezoelectricelements are proportionally reduced, or a distance between edges of twoadjacent piezoelectric elements is reduced by a preset value.
 16. The,screen component of claim 10, wherein each of the piezoelectric layersfurther comprises: a piezoelectric material layer; and an electrodelayer attached to the piezoelectric material layer, wherein an electrodelayer, of a current piezoelectric layer is stacked with a piezoelectricmaterial layer of another piezoelectric: layer adjacent to the currentpiezoelectric layer and the signal line is conductively connected to theelectrode layer.
 17. A mobile terminal, comprising: a processor; and amemory configured to store an instruction executable by the processor;wherein the mobile terminal further includes a screen componentcomprising: a screen body; and a piezoelectric assembly having avibrating member made of a piezoelectric material and a signal lineconnected to the vibrating member including two or more piezoelectricelements stacked in sequence, wherein a size of at least one of thepiezoelectric elements is smaller in size than any remaining one of thepiezoelectric elements to form a stepped structure, each of thepiezoelectric elements is provided with two or more piezoelectric layersof the same size, a piezoelectric element of a largest size of thevibrating member is attached to a surface of the screen body, and thesignal line is communicatively connected to the processor.
 18. Themobile terminal of claim 17, further comprising: a middle frameassembly; and a functional component mounted in the middle frameassembly, wherein the screen component is detachably connected to themiddle frame assembly, and at least part of the functional component islocated in a space corresponding to the stepped structure of thevibrating member.
 19. The mobile terminal of claim 17, wherein thevibrating member is provided with an escape portion adapted to thescreen body, the escape portion being configured into a hole-shapedspace or a notch-shaped space.
 20. The mobile terminal of claim 17,wherein outer peripheral edges of two adjacent piezoelectric elements donot coincide in at least one direction.